Neither LiteOn is faster in sheer performance. They’re almost the exact same drive [with only enough differences that they can’t be crossflashed to the other]. The SATA interface of the 20A1S is there for future-proofing.
Pioneer DVR-215 gives some outstanding writing quality [as does its PATA sibling, the 115], slightly better than LiteOn’s write quality all-around. If you were able to, I’d suggest getting the DVR-215 along with the 20A1P [or S, if you aren’t using the other SATA port], as the two drives complement each other and make up for some weaknesses the other might have [Pioneer cannot scan reliably, LiteOn doesn’t have the best CD writing quality, etc].